Competitive adsorption and dilatational rheology of pork myofibrillar and sarcoplasmic proteins at the O/W emulsion interface

The competitive adsorption behavior of pork sarcoplasmic (SP) and myofibrillar (MP) proteins, alone or mixed (ratios 6:4, 5:5 and 4:6, w/w) in 0.6 M NaCl, at the oil-water interface was investigated. SP adsorbed more rapidly than MP at the oil surface establishing a ~10 mN/m dynamic interfacial pressure (π). However, the dilatational elasticity (Ed) of the SP film was low when compared with MP. For corn oil emulsions prepared with mixed proteins, the poor interfacial adsorption (29%) and low emulsifying activity (3.42 m2/g) of SP were overcome by substitutions with MP that strongly bound to oil. Unabsorbed proteins were mostly SP and secondarily tropomyosin and C-protein from MP. Smaller droplets were observed in MP emulsions than in SP emulsions. Therefore, while both SP and MP contributed to the formation of O/W emulsions, MP played a far more competitive role due to its stronger interfacial adsorption and adhesion properties.